The effect of negative stimulus presentations on observing-response rates

Theories of observing differ in predicting whether or not a signal for absence of reinforcement (S−) is capable of reinforcing observing responses. Experiments in which S− was first removed from and then restored to the procedure have yielded mixed results. The present experiments suggest that failure to control for the direct effect of presenting S− may have been responsible. Pigeons and operant procedures were used. Experiment 1 showed that presentations of S−, even when not contingent on observing, can raise the rate of an observing response that was reinforced only by presentations of a signal (S+) that accompanied a schedule of food delivery. Experiment 2 showed that this effect resulted from bursts of responding that followed offsets of S−. Experiment 3 showed that, when the presence of S− was held constant, lower rates occurred when S− was dependent on, rather than independent of, observing. These results support theories that characterize S− as incapable of reinforcing observing responses.     

Effects of signals preceding and following shock on baseline responding during a conditioned-suppression procedure

Long-Evans rats were exposed to a succession of conditioned-suppression procedures involving pairings of (1) signal-shock, (2) shock-signal, and (3) a signal-shock-signal sequence in which first and second signals were at first physically identical. Traditional suppression of food-reinforced responding was obtained under the signal-shock arrangement, and exposure to the shock-signal sequence resulted in conditioned enhancement of responding during the signal. The signal-shock-signal condition reliably suppressed responding during the first signal, but produced no differential effect on response rate during the second signal. Baseline responding was least changed from preshock rates under the signal-shock-signal procedure, but baseline rate was considerably reduced under the signal-shock and shock-signal arrangements, the latter yielding most substantial reductions. A second experiment indicated that the magnitude and direction of changes in baseline responding reported in Experiment I were not confined to cases in which the first and second signals in the signal-shock-signal arrangement were physically identical. It is suggested that the major effects of the conditioned-suppression procedure on response rate might not be confined to presentations of the signal.     

Converging measures of speech segmentation in preverbal infants

Two studies using novel extensions of the conditioned head-turning method examined contributions of rhythmic and distributional properties of syllable strings to 8-month-old infants' speech segmentation. The two techniques introduced exploit fundamental, but complementary, properties of representational units. The first involved assessment of discriminative response maintenance when simple training stimuli were embedded in more complex speech contexts; the second involved measurement of infants' latencies in detecting extraneous signals superimposed on speech stimuli. A complex pattern of results is predicted if infants succeed in grouping syllables into higher-order units. Across the two studies, the predicted pattern of results emerged, indicating that rhythmic properties of speech play an important role in guiding infants toward potential linguistically relevant units and simultaneously demonstrating that the techniques proposed here provide valid, converging measures of infants' auditory representational units.     

Distractor effect on the latent inhibition of conditioned flavor aversion in rats

Using a conditioned flavor aversion procedure with rats as subjects, the effect of the addition of a distractor stimulus on the magnitude of the latent inhibition effect was examined. Experiment 1 showed that latent inhibition to vinegar was attenuated by the addition of sucrose during preexposure. On the other hand, sucrose added during conditioning to vinegar did not attenuate latent inhibition. It was also found that the degree of latent inhibition to the vinegar-sucrose compound solution was less when vinegar alone was preexposed (i.e., when sucrose was added only during conditioning) than when the compound solution was preexposed (i.e., when sucrose was added both during preexposure and during conditioning). Experiment 2 gave similar results but with sucrose assigned as the target flavor and vinegar as the distractor. These findings are in full agreement with the generalization decrement account of latent inhibition.     

Observing responses maintained by conditional discriminative stimuli.

In a conditional discrimination procedure, pigeons' observing responses were analyzed to examine whether two color stimuli (blue or red), conditionally related to whether each of two line stimuli (vertical or horizontal) accompanied reinforcement or nonreinforcement, functioned as conditioned reinforcers. If a variable-interval (VI) 10-s requirement was fulfilled, an observing response produced onset of a color stimulus. A little later, a line stimulus was presented independently of responding, added to the color stimulus to form a compound stimulus. If 55 s elapsed with a response not having occurred either through 55 s or after the variable-interval 10-s had timed out, one of the color-line compound stimuli was presented independently of responding. To control for sensory reinforcement effects and for earlier entrance to the later link, a simple discrimination procedure also was conducted in which reinforcement was not correlated with the color stimuli but with the line stimuli only. As in the conditional discrimination, the observing response also could produce earlier presentation of blue or red. The observing response occurred more frequently during the conditional discrimination than during the simple discrimination. The results were related to different theoretical accounts of conditioned reinforcement, particularly the information hypothesis.     

Effects of delayed conditioned reinforcement in chain schedules.

The contingency between responding and stimulus change on a chain variable-interval 33-s, variable-interval 33-s, variable-interval 33-s schedule was weakened by interposing 3-s delays between either the first and second or the second and third links. No stimulus change signaled the delay interval and responses could occur during it, so the obtained delays were often shorter than the scheduled delay. When the delay occurred after the initial link, initial-link response rates decreased by an average of 77% with no systematic change in response rates in the second or third links. Response rates in the second link decreased an average of 59% when the delay followed that link, again with little effect on response rates in the first or third links. Because the effect of delaying stimulus change was comparable to the effect of delaying primary reinforcement in a simple variable-interval schedule, and the effect of the unsignaled delay was specific to the link in which the delay occurred, the results provide strong evidence for the concept of conditioned reinforcement.     

AMAs及其靶抗原在原发性胆汁性肝硬化发病中的作用

原发性胆汁性肝硬化（PBC）是一种以慢性进行性胆汁淤积为特点的自身免疫性肝病,血清中抗线粒体抗体（AMAs）,尤其AMA-M2升高是该病的特异性表现.AMAs在PBC发病过程中的作用是研究重点之一.丙酮酸脱氢酶复合物（PDC）的E2亚单位（PDC-E2）是AMAs的主要抗原.诱发AMAs靶抗原暴露和打破免疫耐受的主要诱因是感染及化学因素.后者或与靶抗原交叉反应,或通过对靶抗原的化学修饰,或是使凋亡后抗原的清除发生障碍,从而促进AMAs的产生.针对PDC-E2的细胞免疫主要参与PBC的发病.AMAs在PBC发病中的作用存在争议,更多研究认为其不参与PBC的发病.     

The Effect of Negative Incentives in Serial Learning: VII. Theory of Punishment

Eighty three-, four-, five-, and six-year-old boys and girls were presented with experimental conditions where context, transformational complexity, and verbal cue were varied, Two experimental tasks, a perceptually Concrete and an Abstract task, were included and Ss were assigned to a Verbal Cue or a Nonverbal Cue condition. All Ss responded to both the present progressive and the past tenses. Results revealed significant effects of the Age and Tense factors, and improved performance on Comprehension over Production. Younger children made fewer overall errors than older ones. Ss performed better on the present progressive than on the past tense on the perceptually Concrete task, while the reverse was true on the Abstract task. These findings demonstrate that language performance is the result of a complex interrelationship between transformational complexity and the perceptual properties of linguistic structures.     

The Bodily Self: The Sensori-Motor Roots of Pre-Reflective Self-Consciousness

A bodily self is characterized by pre-reflective bodily self-consciousness that is “immune to error through misidentification.” To this end, the body's double involvement in consciousness is considered: it can experience objects intentionally and itself non-intentionally. Specifically, pre-reflective bodily self-consciousness, by contrast with the consciousness of the body that happens to be one's own, consists in experiencing one's body as the point of convergence of action and perception. Neither proprioception alone nor intention alone is sufficient to underlie this pre-reflective bodily self-consciousness. Rather, it is made possible thanks to a sensori-motor integration, allowing a sensitivity to the sensory consequences of one's action, through action monitoring.     

Terrorism and Innocence

This paper begins with a discussion of different definitions of “terrorism” and endorses one version of a tactical definition, so-called because it treats terrorism as involving the use of a quite specific tactic in the pursuit of political ends, namely, violent attacks upon the innocent. This contrasts with a political status definition in which “terrorism” is defined as any form of sub-state political violence against the state. Some consequences of the tactical definition are explored, notably the fact that (unlike the political status definition) it allows for the possibility of state terrorism against individuals, sub-state groups and other states. But a major problem for the tactical definition is the account to be given of “the innocent.” In line with justwar thinking, the idea of “the innocent” is unpacked in terms of the concept of non-combatants and this in turn is treated as the category of those who are not prosecuting the harm that allows for a legitimate violent response. Problems with this approach are explored, with particular reference to criticisms made by Gregory Kavka. The recent drive to expand the class of those who may be legitimately attacked is subjected to scrutiny. Particular attention is paid to the role of “collective responsibility” and “deserving your government” in these arguments. This revised version was published online in June 2006 with corrections to the Cover Date.